What class of drugs should a therapist administer to a patient in case of an allergic reaction causing vasodilation and decreased blood pressure?

In the context of an allergic reaction causing vasodilation and decreased blood pressure, the appropriate class of drugs to administer would be vasoconstrictors. Allergic reactions can lead to significant vasodilation due to the release of histamine and other mediators, which can result in hypotension.

Vasoconstrictors work by constricting blood vessels, which increases peripheral vascular resistance and ultimately helps to raise blood pressure. This is crucial in cases where the patient is experiencing symptoms of shock or severe hypotension as a result of an allergic reaction.

While vasodilators would further exacerbate the situation by widening blood vessels, and diuretics do not address the urgent need for blood pressure stabilization, antihistamines primarily function to block the effects of histamine and alleviate allergic symptoms but do not directly counteract severe hypotension due to vasodilation. Therefore, administering a vasoconstrictor is the most effective and appropriate therapeutic response in this scenario.